Mr. Davis strode from his vehicle, stopping just feet from the wide traffic median where Kieran Clarke was clearly breaking the law. “Sorry, sir,” he said, “I need to inform you that this area is for walking and jogging only.” Mr. Clarke, who had been working his abdominals, stood up and quietly walked away.

That warning the other day was among hundreds that have been issued in a culturally tumultuous crackdown by Santa Monica officials against violators of a city ordinance, rarely enforced till now, that bars congregating on traffic medians.

The target is increasingly loud, littering and generally intrusive groups of exercisers who gather from dawn until dusk along the Fourth Street median. The ocean view, the air and for some the architectural spectacle have transformed the area into a huge outdoor gym rimmed by multimillion-dollar homes.

In the last six months, park rangers, dispatched by the Santa Monica Police Department in response to complaining neighbors, have stationed themselves on the corner of Fourth Street and Adelaide Drive during much of the day, at the ready to break up any unauthorized kickboxing. “I agree with the residents that they should not be rousted out of bed by a professional gym instructor at 6 in the morning saying, ‘One, two, three, four!’ ” said Bobby Shriver, a Santa Monica city councilman (“Recently re-elected with an even greater margin than I won by last time!”), who lives on Adelaide Drive but says he did not request the enforcement.

Since the patrols began, the city has issued eight citations for the flouting of the median law — the fine is $158 — and has given warnings, which are generally heeded, to about 600 people a month.

“Most people will comply,” said Mr. Davis, the park ranger.

While the median ordinance covers every grassy stretch of its kind in the city, the one at Fourth Street is where the workout overload occurs.

The area has long been a runner’s paradise, and people also use it to sprint up and down an enormous set of concrete steps that lead to the beach. “The use of the median has been going on for years,” Mr. Shriver said, adding that what has apparently happened more recently “is the commercialization by these boot-camp-type groups.”

Naturally a fair share of exercisers are unhappy with the new enforcement, and at a recent City Council meeting, officials batted the matter around: Would the law withstand legal challenges? What constitutes too “early” to be awoken by whistles? But there was no resolution.

Now a community meeting to address median use is set for Jan. 8, “just to see if we can’t get some common-sense solutions,” said Kate Vernez, assistant to the city manager.

Photo

Residents' complaints about noisy exercisers on a Santa Monica traffic median led to enforcement of a law few had heard of.Credit
Monica Almeida/The New York Times

“What we are trying to do,” Ms. Vernez said, “is mediate between residents who have seen an uptick in use of the median, with pickup gyms and the like, and the exercisers.”

James Birch, a music executive from the neighborhood, is among those Santa Monicans who have not taken well to enforcement of the law, which was passed in the 1970s and, it is believed, was intended to keep vagrants away.

After 15 years of working out on the median, Mr. Birch arrived there one day in mid-September and saw five officers. “I went up to them,” he recalled, “and said, ‘What’s the deal here?’ They put up these trendy new yellow signs. The cops just looked at me and said, ‘We’ve been told by the watch commander that we’re supposed to run people off here.’ I told them I was going to break the law.”

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So he did. One morning he showed up at the median, video crew in tow, and refused to cease doing situps. The exchange that followed was posted on YouTube.

“They let me do it for about three minutes,” said Mr. Birch, 63, “and then came over and said: ‘If you continue doing this, I will arrest you. It’s not allowed here.’ ”

Though he was arrested, he said, the officers did not handcuff him, to his chagrin. “I asked them to,” he said. “But they found out they could only do what was procedurally appropriate.”

He did get a ticket, though, and now awaits his day in court.

“I just want to go and do my push-ups and situps that I have been doing for 15 minutes three times a week for the last 15 years,” he said.

On a recent morning, the area was alive with joggers, some of them pushing strollers, others walking large dogs; a dozen people with demeanors ranging from doleful to boastful trotting up the steps; and at least one trainer pushing his client to move it.

An extremely fit woman of indeterminate Los Angeles age pulled her Mercedes up to the curb on Adelaide Drive, popped open her trunk, pulled out a five-pound weight and began lifting.

Geoff Parcells, who was running along the street, said that he sympathized with residents but that the area “is a public place” and that he did not quite know how to view the enhanced enforcement.

“If I lived here and there were all really good-looking people working out, I probably wouldn’t mind,” said Mr. Parcells, 45. “So I guess it depends on who parks in front of your house.”

A version of this article appears in print on , on Page A1 of the New York edition with the headline: Where the Traffic Median Is a No-Pilates Zone. Order Reprints|Today's Paper|Subscribe